The present invention relates to fire detectors, and in particular to a fire detector for being connected in a system with a plurality of detectors.
Fire detection systems, of the type wherein a plurality of fire detectors are positioned at remote locations in a structure, commonly include a central control station for connecting with the detectors. In some such systems, the detectors are individually connected with the control station, whereby upon the occurrence of combustion a signal is provided at the station to indicate the location of the detector sensing combustion. In other systems, the detectors are connected in a loop circuit with the control station, and upon a detector sensing combustion a signal characteristic to that detector, such as a signal at a predetermined frequency, is provided over the loop to the station, whereby the location of the detector generating the signal may be determined by multiplexing techniques.
With these systems, it is possible to improperly interconnect the detectors and the control station, whereby the occurrence of combustion might not be detected. Further, the systems are complex, and not only have a relatively high initial cost, but also a continuing expense as a result of personnel required to monitor the control station. Accordingly, they are primarily advantageous for the early detection of combustion in large structures of sufficient economic value to justify the cost of the system, and where personnel are at all times available to monitor the control station. Unfortunately, for structures such as small office or apartment buildings having a number of individual units, the expense of such systems often cannot be justified.